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2000 Firebird - Electrical - Grounding problem


kat5469
08-15-2007, 01:53 PM
My factory radio/cd will stop working and the power windows will not work too. This is not a constant problem, so when I take it to the dealer they can not trace the problem. They believe it is a grounding problem but cannot figure out where. I'm not sure if there are any other items not working when this happens. Sometimes it will go on for hours and sometimes for seconds and of course never long enough when it is at the dealer. I've also noticed on occassion my car will not start and it is not the battery, cables, starter, alternator, etc. It's like no power what so ever. I wait and re try a few times then it starts. This all first came about when I was having problems with the window motors, that have been replaced several times. Then I finally tied the radio and windows together after I replaced the motors.
:banghead:

cardboardpimp420
08-15-2007, 05:03 PM
i know you said that they are not the battery cables, but im gonna ask this question anyway...have you checked the connections on the battery cables where the cables actually connect to the car?

ikeyballz
08-15-2007, 05:44 PM
+ are the terminals clean? what i had with my camaro and my sisters camaro, is that since they use side posts with plastic covers, you dont see the corrosion under the plastic cover! check those too..

kat5469
08-20-2007, 04:29 PM
i know you said that they are not the battery cables, but im gonna ask this question anyway...have you checked the connections on the battery cables where the cables actually connect to the car?yes, I have checked and cleaned the battery post. The dealer thought they figured it out last week and said it was the ignition switch and replaced it and took care of some wires in the junction, 2 days later the same problem but for just a few seconds and then again today for maybe a minute or so. This happens while I am driving.:disappoin

kat5469
08-20-2007, 04:32 PM
i know you said that they are not the battery cables, but im gonna ask this question anyway...have you checked the connections on the battery cables where the cables actually connect to the car?YES!

ikeyballz
08-20-2007, 06:42 PM
does it happen when you go over a bump/etc? or just..randomly? have you been blowing fuses? or it just sporadically goes out? and comes back on? when you're looking under the hood, can you spot any shorts/ burn marks/ melted wires?

when youre running the car and it happens, does your car shut off? (no power to spark plugs?)

LtWizzard
08-26-2007, 03:16 PM
My Firebird 2000 has the same problem. It has been going on for many months now. Took it to the dealer, but they could not duplicate the problem since it is intermitent. :banghead:

I will be just driving along and the radio and window controls will stop working. Sometimes for a few seconds, sometimes for many minutes. Using the lock/unlock swith sometimes restores power as opening and closing the door will, but I have not found a sequence that works all the time. Sometimes I just have to wait.

Since all power for both the radio and power windows comes from the body control module (BCM) either the BCM is bad or wiring from the module to the fuse block on the driver's side dash is bad. The dealer tested the BCM and said there were no error code, so the unit is good. But if the module has a relay within it, then a relay could be intermitent, but since the computer is runing OK, it would not register any errors. I could replace the BCM for $200, but that is an expensive gamble if I am wrong. :shakehead

Any additional help would be helpfull. If I brake down and get a new BCM, I will let you know the results.

Charles

kat5469
08-29-2007, 10:49 AM
does it happen when you go over a bump/etc? or just..randomly? have you been blowing fuses? or it just sporadically goes out? and comes back on? when you're looking under the hood, can you spot any shorts/ burn marks/ melted wires?

when youre running the car and it happens, does your car shut off? (no power to spark plugs?)
Yes, sometimes over bumps but not always, not consistent. Last time I took it to the dealer they said it was the Starter Switch they replaced it and let it run for hours and no problem, next day it cuts out for a second, 2nd day cuts out again, and now it does it all the time. I also found out that when the radio shorts out and the power windows don't work, the convertible top also does not work.....these are all that I have tied together....never any problems with fuses. They claim they found some problems with the wires to the starter switch. I had told them on a few occasions the car would not start and then it would.....all inconsistent so hard to detect.

kat5469
08-29-2007, 10:53 AM
does it happen when you go over a bump/etc? or just..randomly? have you been blowing fuses? or it just sporadically goes out? and comes back on? when you're looking under the hood, can you spot any shorts/ burn marks/ melted wires?

when youre running the car and it happens, does your car shut off? (no power to spark plugs?)

No, the car never shuts off, don't see any bad or melted wires, and the car is back at the dealer today for at least the 4th time.:banghead:

kat5469
08-29-2007, 10:58 AM
My Firebird 2000 has the same problem. It has been going on for many months now. Took it to the dealer, but they could not duplicate the problem since it is intermitent. :banghead:

I will be just driving along and the radio and window controls will stop working. Sometimes for a few seconds, sometimes for many minutes. Using the lock/unlock swith sometimes restores power as opening and closing the door will, but I have not found a sequence that works all the time. Sometimes I just have to wait.

Since all power for both the radio and power windows comes from the body control module (BCM) either the BCM is bad or wiring from the module to the fuse block on the driver's side dash is bad. The dealer tested the BCM and said there were no error code, so the unit is good. But if the module has a relay within it, then a relay could be intermitent, but since the computer is runing OK, it would not register any errors. I could replace the BCM for $200, but that is an expensive gamble if I am wrong. :shakehead

Any additional help would be helpfull. If I brake down and get a new BCM, I will let you know the results.

Charles The Dealer said they didn't find a problem with the BCM or wiring from the module. That was one of the first things they thought it was. Your problem sounds exactly the same as mind. I've not had any problems with the door locks. I would check them to see if they worked when the radio and windows would not and they always did and didn't seem to restore or change anything.
What dealer did you go to? I'm in Houston, TX.:banghead:

LtWizzard
09-04-2007, 03:34 PM
kat5469,

I took it to Bob Daniels, a GMC dealer here in Columbus, Ohio.

Today, opening and closing the door didn't help. It stayed off for a few minutes, and then on/off/on interment four or five times, then stayed on.

I am in electronics and computers, so I understand how the body control module works, but I am not privy to the logic tree that GMC uses that control the unit, so it is very difficult to troubleshoot. Here is what I have compiled so far:

The power staying on for the windows, radio and convertible top are options know as the retained accessory power (RAP) option, which is controlled by the BCM. There is a single wire between the BCM and the fuse block that holds the fuses for the windows, radio and convertible top. The BCM has some type of electronics control inside (mechanical or solid-state relay) that switches between power controlled by the ignition switch (on when ignition is turned on) and a time-delayed power (10 minutes) source, the RAP.

The BCM receives inputs from the door switches and the ignition switch. When the ignition switch is on, power is in normal mode and is feed to the line to the fuses. But when the doors remain shut and the ignition key is removed (after having been on and the engine running) the BCM selects the RAP power source, which stays on for ten minutes or until the BCM receives a signal from one of the doors when they are opened. At which time the BCM switches back to the normal ignition source, which has no power because the ignition switch is off (key has been removed).

Now the strange thing is that we both are losing ALL power while the ignition switch is on, which means something in the BCM is stopping it or the wire between the BCM and the fuse block is intermittently open. I have also noticed that the radio, etc. do not stay on as designed (i.e. the RAP option) when the ignition key is removed. This is also interment, but seems to happen after the power losses have occurred while driving. I believe this adds more support to my theory that it is something inside the BCM rather then an intermittent in the wire. Something is malfunctioning within the BCM that generates no error codes, but causes a disruption of power on the down side of the control source. I am starting to gain the courage to swap the BCM out and see it that fixes it. It will cost $200, but this intermittent stuff is driving me crazy. I listen to a lot of books on CD, so it is more then just music stopping and going.

Hope you can follow all that, if not, ask me some questions and I will try to clarify. Perhaps your dealer would be more willing to listen to you or read a copy of my replay. My dealer more or less was sympathetic, but had the attitude that if it wouldn’t do it for them, then it’s not broken and there is nothing they could do.

Good luck.

kat5469
09-05-2007, 08:44 AM
My Firebird 2000 has the same problem. It has been going on for many months now. Took it to the dealer, but they could not duplicate the problem since it is intermitent. :banghead:

I will be just driving along and the radio and window controls will stop working. Sometimes for a few seconds, sometimes for many minutes. Using the lock/unlock swith sometimes restores power as opening and closing the door will, but I have not found a sequence that works all the time. Sometimes I just have to wait.

Since all power for both the radio and power windows comes from the body control module (BCM) either the BCM is bad or wiring from the module to the fuse block on the driver's side dash is bad. The dealer tested the BCM and said there were no error code, so the unit is good. But if the module has a relay within it, then a relay could be intermitent, but since the computer is runing OK, it would not register any errors. I could replace the BCM for $200, but that is an expensive gamble if I am wrong. :shakehead

Any additional help would be helpfull. If I brake down and get a new BCM, I will let you know the results.

Charles I asked the dealer to chec the BCM again and they did, but decided to change out the control module for the windows, which so far so good. But when I took my car in last week the Service Engine Soon - light came on and was still on when I picked up my car, 2 days later it went off, then has come back on again.....but at least now my radio, window motors and convertible top motor all are working........:)

LtWizzard
09-08-2007, 01:45 PM
When you say they replaced the window contorl module, was that the BCM or something else? Not sure what they ment by window control module since everthing is controlled out of the BCM on our model of Firebird.

Not sure why your check engine light would come on, especially since you had it at the Dealer. Hope it is something simple to replace or fix like an oxgen sensor.

Keep in touch and let me know if what they did really does fix the problem over the next few weeks. If they did change the BCM, I will do the same.

Thanks for the feedback! The Internet is wonderful when you have problems like this.

acaba
10-13-2007, 07:17 PM
Kat,

I have had the same problems with my radio and windows going out intermittently for about 6 months now. If I listened carefully I could hear the relay in the BCM clicking every time the power cycled. I checked the connections and everything is fine, so I think the problem was in the BCM.

I finally removed the BCM and opened it up. I found that one of the solder joints was cracked on the relay that controlls the power to the window & radio fuzes. I tried to heat up the solder joint to reflow it, but unfortunately I put too much solder on the joint and shorted something out. When I pluged it back in I let the magic smoke out of one of the ICs. Now the windows and radio work, but the door lock button seems to be cross connected to the trunk latch and the fasten seat belt light. And one of the chips on the board is kinda cracked and has goo leaking out of it. Guess this just proves that I'm truly a mechanical engineer, not an electrical engineer!

Anyway, I will try to replace the BCM tomorrow or the next day and see if my radio and windows keep working and the problem goes away.

Aaron

LtWizzard
10-23-2007, 07:39 PM
Aaron,
I suspected something like that as I had said in my earlier responses. I have noticed that since it has gotten cooler (I live in Columbus, Ohio), that the radio/windows are not acting up. That would confirm that it could be a crack in the PC foil. Heat expands, cold contracts, but then you know that if you are a mechanical engineer. My background is electronics, so I just might take a look at mine this weekend. Thanks for the replay and I will check back to see how things work out for you.

acaba
11-09-2007, 11:18 PM
I finally got my new BCM from the dealer and it only took 2 weeks. First they orderd a _P_CM (powertrain computer module) that took 4 days. Then they orderd a BCM (2 days + Sat + Sun) but it was USED and already had the security key code burned in so the car would not start. I finally got a new BCM (3 days + Sat + Sun).

Once I installed the new BCM everything works fine. It has been cool out, but not a single problem with the window/radio for almost 2 weeks now.

You can remove and open up the BCM really easily (at least on the '96 Camaro) for testing. I put an ohm-meter across the relay that controls the window/radio and found that by flexing the board I could make the resistance jump. My mistake was trying to artifically actuate the realy. I took an 18V battery pack and jumpered across the control side of the relay to see if it would energize and close the contacts correctly. Not sure if I reverse biased something or if my bad soldering job caused a short, but I really fried one of the ICs when I activated the realy after my fix.

Hope this helps you diagnose your problems.

Aaron

P.S.: Do you have a copy of the GM service manuals? I bought them for ~$160 and they have easily saved me that much in repair bills. I don't mean the crappy Haynes manuals, I mean the 4" thick GM manuals. They really help when tracing circuits, or even just trying to remove the dash board.

Sevenpelicans
05-24-2008, 02:28 PM
HI,

I believe I am having the same windows radio problem. Actually I know I am having the problem. It happens all the time. However, I am assuming it is from the BCM like many of you have experienced. I purchased a BCM on ebay. The guys said it was new but, I have no idea if it is. I am curious if anyone has any information on how to go about installing the BCM? I understand there is some way of programming it to the car and remote lock key chain? Any info would be appreciated? Also, does anyone know if it can be reset or does it absolutely have to be brand new? Thanks for your time. This thread has really given me some idea's on how to fix my radio problem.

Wattsyurz
05-25-2008, 12:46 AM
The thread was quite old, I wonder if there was a resolution. I had a similar problem with my '00 Vette, where the driver door had connections that needed tightening. If closing doors and bumps affected the symptom, I would have voted on a mechanical fix like my loose connector. When the connection would go out, several things went including the radio, TCS, windows, locks, even the fuel gauge! I found that closing the door firmly would bring it back, which led me to examine the connectors in the door. I haven't had my '00 T/A door panels off, but the connectors are probably of the same quality. The female portions of the pins were notably oversized on a few of the connections, and can be carefully nudged tighter. Let me know if you find something. Even though I haven't seen this problem yet it would be good to know.

Sevenpelicans
05-26-2008, 11:31 PM
Alright. So, I replaced the BCM on my 2000 Camaro today. Its seemed to do the trick for the radio windows problem. I tried both of the BCM's a few times and for some reason even without any movement the old BCM would just lose power to the windows and radio. I looked at all the wiring and the connecdtors everything looks good. The new BCM hasn't done it since. So, I was pretty happy. THe only problem I ran into was that my BCM wasn't exactly new. I bought it on ebay and the guy who sold it had already installed it. When I put it in it worked, and the car started but, the security light would not go away. After following the manual instruction for programming the BCM I still couldn't get the security light to go off. I reprogrammed it to the keyless entry and that worked fine but, still the security light is on. The manual says that a BCM can only be programmed once and is programmed to the car the first time its installed and the ignition is turned on. Does anyone know how I could just shut the security light off? I don't know if its affecting the alarm but its definetly not affecting anything else.

1sadboy
09-23-2008, 11:26 PM
I own a 1996 firebird with exact symptoms. Radio and window would intermittently go inoperative. In high heat days, it seemed the problem was more severe. I repaired my vehicle today!!! :cool: Yee ha. It is definetly the Body Control Module, which is located behind the glove box, accessed by removing the panel directly beneath. There are 3 (looks like 2, but there are 3) multi-pin connectors in the BCM. Easy to spot from there. Disconnect the connectors and slide the BCM down and out. Takes a little effort. There was a cold solder joint on one of the 4 relays in this box. Simply touch a pencil tiped soldering iron to each of the solder joints. It's worth you while trying to fix your BCM, as your remotes are programmed via this module, and it's also matched to your ignition key resistor (for anti-theft measures). Replacing with a used BCM will take some working around these issues, and buying new will cost you -:banghead: Good luck.

oldgray
04-02-2009, 06:56 AM
My '97 has the same problems too. I took out the BCM and saw a solder connection that looked iffy so I fixed it. The radio and windows are still working off and on but my wife found that they work if she applies pressure to the dash on the right side of the radio. I'm assuming that the dash applies pressure to the radio which applies pressure to a wire harness back there. I removed the radio and looked in there and everyone looks and feels okay. Any idaes?

Ralph123
02-05-2010, 05:29 PM
I have to correct my last post. The spark plug wire DIDN'T fix the windows-radio loss of power problem. The problem is definitely in the BCM (body control module). I unplugged the 3 connections to the BCM and plunged them back in and it fixed the problem. My solder joints looked OK. You have to use a screw driver and push in on the sides of the 2 smaller connections to disconnect them. If you want to pull the BCM all the way out here's a tip. with your fingers pull the bottom of the plasctic housing hard toward you while you push the the BCM back out of the housing then you will be able to pull it down and out. I know this thread is old but this is one of the first links that comes up if you Google this problem. Hopefully this will be the last word on this problem. Here's another great link with pictures and instructions about this problem. thanks
http://www.ls1tech.com/forums/general-lsx-automobile-discussion/883334-ls1-body-control-module-problems-fix.html

Ralph123
02-11-2010, 10:10 AM
"Holy thread revival Batman."
After a year of dealing with this problem of intermittent loss of power to my power windows, radio and convertible top (all happening at the same time) I was able to fix it by putting a drop of solder on some circuit joints in the BCM (body control module.)
At first I thought it was it was just loose connection at the wire harnesses but that wasn't it.
The hardest part is getting the BCM out. It's located behind the glove box. You can see the BCM if open your glove box and pull the sides of the glove box in and the glove box will drop all the way to the floor but you can't remove it through the glove box opening. You have to remove the bottom panel and side panel the push the the BCM back while you pull the plastic housing toward you to free it from the housing so you can pull it down and out.
If you don't feel comfortable soldering you could try using a conductive epoxy. Dupont makes some for repairing rear window defoggers.
Below is a photo of the BCM circuit board with the 5 joints in question. They are the large joints shaped in a T. The hairline cracks in these joints are very small. I had to use a magnifying glass to see it but they are there.
Click photo below to enlarge
and here is another link that deals with the same problem.>>> http://www.ls1tech.com/forums/general-lsx-automobile-discussion/883334-ls1-body-control-module-problems-fix.html

oldgray
03-30-2010, 06:25 AM
Ralph, thanks for the link and the picture, I tried this once before but I wasn't sure which solder joints I should check or the need for a magnifying glass. I guess I'll give it another shot this weekend. Otherwise, I'm going to disconnect the stereo from the BCM controlled power supply and tie it in with the cigarette lighter or something else that's handy. I can live with the windows working off and on. We live on the coast and everytime we go over a bridge, the stereo freaks out.

pharaohxander
07-03-2010, 04:41 PM
This was very helpful. I have been having the same trouble with the windows/radio turning off while driving. I re-soldered the relay connection per the photo above and it fixed the problem. took me maybe 30 min (most of which was spent removing the module from the car and making a soldering iron since i dont have one lol.)

PS wrapping piece of 10 gauge copper grounding wire around the nozzle of a propane torch makes a great soldering iron. just bend the end of the wire 90 degrees across the flame so that you dont torch the circuit (flame up, wire tip down)

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